Orthodontic treatment involves the application of mechanical forces to urge improperly positioned teeth into correct alignment. One form of orthodontic treatment includes the use of orthodontic brackets respectively fixed to individual teeth either by bands or, more commonly, fixed into place with adhesive. After the brackets are fixed to the teeth of the upper or lower arch, a resilient archwire is then seated in the archwire slots of the upper or lower brackets. The upper and/or lower teeth may be treated in this manner. The archwire(s) may then be secured in place with respect to each bracket by individual ligature wires or elastic bands. This results in active ligation or, in other words, ligation that forces the archwire to the base surface of the archwire slot.
Alternative bracket designs ligate the archwire into position by a movable closure member or cover. Such movable closure members may be permanently, but movably, coupled with the bracket body or may be a separate element non-permanently coupled with the bracket body. These types of archwire slot closure members may ligate the archwire either passively or actively. In passive designs, the closure member does not force the archwire to the base surface of the archwire slot but, instead, allows the archwire, or at least a portion thereof, to be spaced from the base of the archwire slot or from the movable closure member. In contrast, in active ligation, the movable closure member or other ligating element forces the archwire to the base surface of the archwire slot. The movable closure member is opened for inserting the archwire into the slot and then closed for retaining the archwire in the archwire slot. This movable closure member includes, but is not limited to, a ligating slide, a clip, an elastic or resilient cover, etc. Correction occurs as the archwire aligns the teeth to the shape of the archwire.
There is a need for an orthodontic bracket that provides consistent rotational control of the tooth and an improved method for controlling rotation of the tooth during treatment.